Pr
o
Minent
®
Page 54
H
2
O
2
* If the reference electrode has a silvery sheen or looks white, it needs to be regenerated.
Brownish-grey discolouration is however normal.
** To isolate faults, the current in the sensor can be displayed via the DULCOMETER
®
D1C whilst
the latter is electrically connected to the sensor.
For this purpose read the value in “zero point” in the setting menu “H
2
O
2
calibration” in the
complete operation menu, see operating instructions DULCOMETER
®
D1C, chap. 8. Do not
confi rm by pressing the Enter key, but exit the menu using the Back key.
8.3.4
DULCOMETER
®
D1C Measured Variable H
2
O
2
and DULCOTEST
®
PER
Sensor for Hydrogen Peroxide, Maintenance
Controller
The
DULCOMETER
®
controller type D1C for the measured variable H
2
O
2
is maintenance-free.
Sensor
IMPORTANT
Maintain the sensor regularly in order to avoid over metering in a control system result-
ing from an incorrect measured value!
Observe the relevant national regulations in force for fre quency of maintenance!
Do not touch the electrodes or bring them into contact with greasy substances!
Do not unscrew the membrane cap when cleaning the membrane!
Maintenance interval
Figures based on experience for: media with minor dirt contamination: 1 month
Other applications:
depending on operating conditions
Fault
Possible cause
Remedy
Sensor measured
value is 0 ppm
Sensor measured
value is 0 ppm and error
message appears at the
DULCOMETER
®
D1C
controller “H
2
O
2
input
< 3 mA”
Sensor measured value is
0 ppm and sensor current
is between 3.0 and 4.0 mA**
Error message at
DULCOMETER
®
D1C
controller “H
2
O
2
input
> 23 mA“
Sensor measured
value is unstable
No electrolyte in the
diaphragm cap
Sensor connected to controller
with incorrect polarity
Signal cable broken
Defective sensor
Defective control equipment
Running-in time too short
Defective reference electrode*
H
2
O
2
content exceeds upper
limit of measuring range
Defective sensor
Defective reference electrode*
Process-related
Use new diaphragm cap
and fi ll in new electrolyte
(see “Mounting”,
“Running-in Period” and
“Calibration”
Connect the sensor correctly
to the controller
Change signal cable
Return the sensor
Check the control equipment
with sensor simulator
(DULCOMETER
®
Simulator,
order no.1004042), return
if defective
See “Running-in time”
Return the sensor for
regeneration
Check system, remedy the
defect repeat calibration
Return the sensor
Return the sensor for
regeneration
Optimise control process
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BA_DR_002_02_09_GB_Cooling.indd 54
24.02.2009 11:56:06 Uhr
24.02.2009 11:56:06 Uhr